U.S. patent number 4,293,861 [Application Number 06/110,493] was granted by the patent office on 1981-10-06 for compact television antenna system.
This patent grant is currently assigned to Winegard Company. Invention is credited to Keith B. Cowan, Carey W. Shelledy, John R. Winegard.
United States Patent |
4,293,861 |
Winegard , et al. |
October 6, 1981 |
Compact television antenna system
Abstract
A highly compact and lightweight 82 channel all banded VHF-UHF
television antenna having three antenna elements wherein each
element is the identical physical length and each element includes
two half sections. Each antenna element is separated a
predetermined distance from each other element wherein the
predetermined distance is substantially less than one-tenth of the
shortest wave length in the VHF band. A first set of coils are
utilized to electrically lengthen the halves of the two elements
for reception in the VHF band and a second set of coils are
utilized to provide proper delays between the signals received by
each antenna element so that when the signals are combined the
signals are substantially additive and in phase. The antenna system
includes a weatherproof housing containing a rotor, a preamplifier,
and electronic circuitry. A deloading mechanism is arranged around
the housing to engage the circumference of each antenna element to
provide stability under the driving forces that may occur in the
atmosphere.
Inventors: |
Winegard; John R. (Evergreen,
CO), Shelledy; Carey W. (Lakewood, CO), Cowan; Keith
B. (Arvada, CO) |
Assignee: |
Winegard Company (Burlington,
IA)
|
Family
ID: |
22333310 |
Appl.
No.: |
06/110,493 |
Filed: |
January 8, 1980 |
Current U.S.
Class: |
343/766; 343/809;
343/816; 343/872; 343/883 |
Current CPC
Class: |
H01Q
1/24 (20130101); H01Q 3/02 (20130101); H01Q
5/371 (20150115); H01Q 9/44 (20130101); H01Q
5/335 (20150115); H01Q 9/10 (20130101) |
Current International
Class: |
H01Q
9/04 (20060101); H01Q 3/02 (20060101); H01Q
1/24 (20060101); H01Q 9/10 (20060101); H01Q
5/00 (20060101); H01Q 9/44 (20060101); H01Q
003/00 (); H01Q 021/00 () |
Field of
Search: |
;343/812-816,872,880,766,809,883 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
RCA, AC-DC Mini-State Antenna System Operating Instructions,
3F4511..
|
Primary Examiner: Lieberman; Eli
Attorney, Agent or Firm: Dorr; Robert C.
Claims
We claim:
1. A low and high band VHF and UHF antenna comprising:
an elongated support having a front directed at a source of low and
high band VHF and UHF signals, a rear and substantially
longitudinal sides,
a first element having two half sections mounted to said support
located on said longitudinal sides and near said rear of said
support, each of said first element half sections having one end
affixed to said support and being oriented directly opposing each
other, said first element being capable of substantial reflection
of said high VHF signals,
a first pair of lengthening coils mounted on said support in
substantial alignment with said first element, each of said first
pair of lengthening coils having one end connected to the aforesaid
affixed end of said first element half section, said first element
half sections in cooperation with said first pair of lengthening
coils being capable of substantial resonance in the lower portion
of the low VHF band for receiving first low VHF signals,
a second element having two half sections mounted to said support
located on said longitudinal sides and near the center of said
support, each of said second element half section having one end
affixed to said support and being oriented to form an open V-shaped
configuration, the open end of the aforesaid V-shaped configuration
being directed toward said front of said support, said second
element being capable of substantial reflection of said UHF
signals,
a second pair of lengthening coils mounted on said support in
substantial alignment with said second element, each of said second
pair of lengthening coils having an end connected to the aforesaid
affixed one end of said second element half sections, said second
element half sections in cooperation with said second pair of
lengthening coils being capable of substantial resonance in the
high portion of the low VHF band for receiving second low VHF
signals, said second element half sections in cooperation with said
second pair of lengthening coils being further capable of
substantial resonance in the low portion of the high VHF band for
receiving first high VHF signals,
a first pair of delay coils having inductance mounted on said
support, each of said first delay coils connected on one end to the
ends of said first pair of lengthening coils not connected to said
first element half sections, each of said first delay coils being
connected on the other end to the ends of said second pair of
lengthening coils not connected to said second element half
sections, said first pair of delay coils being oriented
substantially parallel to the longitudinal axis of said support,
said first pair of delay coils being capable of delaying said first
low VHF signal sufficiently to produce a combined low VHF signal
having a phase relationship between said first low VHF signal and
said second low VHF signal that is substantially additive,
a third element having two half sections mounted to said support
located on said longitudinal sides near said front of said support,
each of said third element half sections having one end affixed to
said support and being oreinted to form an open V-shaped
configuration, the open end of the aforesaid V-shaped configuration
being directed toward said front of said support, said third pair
of elements being capable of substantial full-wave resonance in the
high portion of the high VHF band for receiving second high VHF
signals, said third pair of elements being capable of substantial
multiple wavelength resonance in the UHF band for receiving UHF
signals,
a second pair of delay coils having inductance mounted on said
support, each of said second delay coils connected on one end to
the ends of said second set of lengthening coils connected to said
first pair of delay coils, each of said second delay coils being
connected on the other end to said affixed ends of said third
element half sections, said second pair of delay coils being
oriented substantially parallel to said longitudinal axis, said
second pair of delay coils being capable of delaying said first
high VHF signal sufficiently to produce a combined high VHF signal
having a phase relationship between said first high VHF signal and
said second high VHF signal that is substantially additive, and
means receptive of said combined low VHF signal, said combined high
VHF signal and said UHF signal for delivering the aforesaid signals
from said antenna.
2. The antenna of claim 1 wherein the physical length of said
first, second, and third elements are the same length.
3. The antenna of claim 1 wherein the physical spacing between said
first and said second elements and the physical spacing between
said second and third elements are each less than one-tenth the
wavelength of the highest frequency in the high VHF band.
4. A low and high VHF and UHF television antenna comprising:
an elongated support having a front directed at a source of low and
high band VHF and UHF signals, a rear and substantially
longitudinal sides,
a first element having two half sections mounted near said rear of
said support, the aforesaid element being oriented substantially
perpendicular to said longitudinal sides in a horizontal plane,
said first element being capable of substantial reflection of said
high VHF signals,
means cooperative with said first element for receiving a first low
VHF signal by enabling said first element to substantially resonate
in the lower portion of the VHF band,
a second element having two half sections mounted in the center of
said support, the aforesaid element laying in said plane with each
of the aforesaid half sections being oriented to form an open
V-shaped configuration, the open-end of the aforesaid V-shaped
configuration being directed toward said signal source, said second
element being capable of substantial reflection of said UHF
signals,
means cooperative with said second element for receiving a second
low VHF signal by enabling said second element to substantially
resonate in the high portion of the low VHF band and for receiving
a first high VHF signal by substantially resonating in the low
portion of the high VHF band,
means connected to said first and second elements for producing a
combined low VHF signal by combining said first and second low VHF
signals together in a substantial phase relationship,
a third element having two half sections mounted near the front of
said support, the aforesaid element laying in said plane with each
of the aforesaid halves being oriented to form an open V-shaped
configuration, the open-end of the aforesaid V-shaped configuration
being directed toward said signal source, said third element
receiving a second high VHF signal by substantially resonating in
the high portion of the high VHF band and receiving a UHF signal by
substantially resonating in the UHF band,
means connected to said second and third elements for producing a
combined high VHF signal by combining said first and second high
VHF signals together in a substantial phase relationship, and
means receptive of said combined low VHF signal, said combined high
VHF signal and said UHF signal for delivering the aforesaid signals
from said antenna.
5. The antenna of claim 4, wherein the physical length of said
first, second, and third elements are the same length.
6. The antenna of claim 5 wherein said physical length is 27
inches.
7. The antenna of claim 4 wherein the spacing between said first
and said second elements and between said second and third elements
are each less than one-tenth the wavelength of the highest
frequency in the high VHF band.
8. A low and high band VHF and UHF antenna comprising:
an elongated support having a front directed at a source of low and
high band VHF and UHF signals, a rear and substantially
longitudinal sides,
a first element directed towards said source mounted near said rear
of said support, said first element being capable of substantial
reflection of said high band VHF signals,
means cooperative with said first element for receiving a first low
VHF signal by enabling said first element to substantially resonate
in the lower portion of the VHF band,
a second element directed towards said source mounted in the center
of said support and spaced less than one-tenth of the wavelength of
the highest frequency in the high VHF band from said first element,
said second element being capable of substantial reflection of said
UHF band signals,
means cooperative with said second element for receiving a second
low VHF signal by enabling said second element to substantially
resonate in the high portion of the low VHF band and for receiving
a first high VHF signal from substantial resonance in the low
portion of the high VHF band,
means receptive of said first and second low VHF signals for
combining said signals together in a substantial phase relationship
to produce a combined low VHF signal,
a third element directed towards said source mounted near the front
of said support and spaced less than one-tenth of the wavelength of
the highest frequency in the high VHF band from said second
element, said third element being capable of receiving a second
high VHF signal by substantially resonating in the high portion of
the high VHF band and of receiving a UHF signal from multiple wave
resonance in the UHF band,
means receptive of said first and second high VHF signals for
combining said signals together in a substantial phase relationship
to produce a combined high VHF signal, and
means receptive of said combined low VHF signal, said combined high
VHF signal and said UHF signal for delivering the aforesaid signals
from said antenna.
9. The antenna of claim 8 wherein said first, second, and third
elements are each the same length.
10. An antenna directed at a source of low and high band VHF and
UHF signals comprising:
a first element, said first element being capable of substantial
reflection of said high band VHF signals,
means cooperative with said first element for receiving a first low
VHF signal by enabling said first element to substantially resonate
in the lower portion of the VHF band,
a second element oriented closer to said signal source than said
first element and in the same plane as said first element, said
second element being capable of substantial reflection of said UHF
band signals,
means cooperative with said second element for receiving a second
low VHF signal by enabling said second element to substantially
resonate in the high portion of the low VHF band and for receiving
a first high VHF signal by substantial resonance in the low portion
of the high VHF band,
means receptive of said first and second low VHF signals for
combining said signals together in a substantial phase relationship
to produce a combined low VHF signal,
a third element oriented closer to said signal source than said
second element and in the same plane as said second element, said
third element being capable of receiving a second high VHF signal
by substantially resonating in the high portion of the high VHF
band and of receiving a UHF signal through multiple wave resonance
in the UHF band,
means receptive of said first and second high VHF signals for
combining said signals together in a substantial phase relationship
and for producing a combined high VHF signal, and
means receptive of said low combined VHF signal, said combined high
VHF signal, and said UHF signal for delivering the aforesaid
signals from said antenna.
11. The antenna of claim 10 wherein said first, second, and third
elements are of the same physical length.
12. The antenna of claim 10 wherein the physical spacing between
said first and said second elements and the physical spacing
between said second and third elements are each less than one-tenth
the wavelength of the highest frequency in the high VHF band.
13. A low and high band VHF and UHF antenna comprising:
a longitudinal support,
a first element mounted near the rear of said support, said first
element being oriented to lay in a plane substantially
perpendicular to the longitudinal axis of said support,
a second element mounted in the center of said support, said second
element being oriented to lay in said plane and to form an open
V-shaped configuration having an apex angle of substantially 135
degrees, the open end of the aforesaid V-shaped configuration being
directed toward the front of said support, and
a third element mounted near the front of said support, said third
element being oriented to lay in said plane and to form an open
V-shaped configuration having an apex angle of substantially 60
degrees, the open end of the aforesaid V-shaped configuration being
directed toward the front of said support, said first, second and
third elements being of equal length.
14. The antenna of claim 13 wherein the spacings between said first
and said second elements and between said second and said third
elements are less than one-tenth the wavelength of the highest
frequency in the high VHF band.
15. An antenna for combining electromagnetic signals at a
predetermined frequency received by a first antenna element having
first and second end-driven half sections and electromagnetic
signals at said predetermined frequency from a second antenna
element having first and second end-driven half sections, said
first and second elements being spaced apart a predetermined
distance in the same plane on the same longitudinal support, said
antenna comprising:
a first inductor coil containing a predetermined amount of
inductance having one end connected to the output of said first
half section of said first element and having its second end
cross-connected to one of the outputs of said half sections of said
second element, said first inductor being oriented in said plane
substantially perpendicular to said first element, and
a second inductor coil containing said predetermined amount of
inductance having one end connected to the output of said second
half section of said first element and having its second end
cross-connected to the remaining output of said half sections of
said second element, said second inductor being oriented in said
plane substantially parallel to said first inductor, said first and
second inductors capable of delaying the received electromagnetic
signals from the first element sufficiently to be in phase with the
received electromagnetic signals from the second element,
said predetermined amount of inductance in said first and second
coils being sufficient to reduce said predetermined distance to
less than substantially one-tenth the wavelength of said
predetermined frequency, said first and second elements being of
equal physical length, and said second element having its half
sections oriented to form an open V-shaped configuration opening
forward and in front of said first element.
16. The antenna of claim 13 further comprising each of said first,
second and third elements having a first end of said element
affixed to a terminal mounted in said support and having the second
end of said element freely extending into the atmosphere, said
support comprising means engaging the circumference of each of said
elements at a predetermined distance from said affixed end for
supporting said element, said supporting means being capable of
flexing through a predetermined apex angle when each of said
elements are subjected to moment forces by said atmosphere, said
apex angle being oriented substantially perpendicular to the plane
in which said terminal and said element lay, said supporting and
deloading means being capable of minimizing any forces at said
terminal.
17. The antenna of claim 16 wherein said means comprises:
a housing containing said terminal,
a first flexible lip extension from said housing oriented in a
plane above and parallel to the plane in which said elements reside
in, said upper lip extension having a downwardly extending means
for engaging the upper circumference portion of each of said
elements at said predetermined distance, and
a second flexible lip extension from said housing oriented in a
plane below and parallel to the plane in which said elements reside
in, said lower lip extension having an upwardly extending means for
engaging the lower circumference portion of each of said
elements.
18. The apparatus of claim 17 wherein said upper lip extension
abuts the upper surface of each said elements substantially along
the entire length of said predetermined distance.
19. The antenna of claim 13 further comprising:
a support mast connected to said support for use in the room of a
building, said room having a floor and a ceiling, said support mast
being capable of engaging said floor and ceiling of said room in an
orientation substantially vertical to said floor,
a hollow housing having a front, a back, top, bottom and
longitudinal sides, said housing having formed holes in said top
and bottom of said housing, said formed holes being aligned and
being capable of receiving said support mast therethrough, and
means in said housing for holding said support.
20. The antenna system of claim 19 further comprising means in said
housing for selectively rotating said housing about said support
mast.
21. The antenna of claim 13 further comprising:
a support mast,
a hollow weatherproof housing having a front, back, top, bottom and
longitudinal sides containing said longitudinal support, said
housing having a formed hole in said bottom for receiving one end
of said mast,
means for releasably connecting said hollow housing to said support
mast, and
means mounted through said housing for extending said signals from
said first, second, and third elements.
22. The antenna of claim 21 wherein said connecting means is
capable of receiving any one of a plurality of support masts having
different diameters.
23. The antenna of claim 21 further comprising a preamplifier
selectively mounted in the interior of said housing, said
preamplifier being further interconnected with said first, second,
and third elements for amplifying said signals, said amplified
signals being delivered to said extending means.
24. The antenna of claim 21 further comprising:
means capable of being mounted on the interior of said housing and
engaging said support mast for rotating said entire housing about
said support mast,
means external of said housing for generating rotate signals in
response to a manual input, and
means for extending said rotate signals from aforesaid generating
means through said housing to said rotate means.
25. The antenna of claim 21 further having drain holes formed in
said bottom of said housing.
26. The antenna of claim 21 further comprising:
a preamplifier selectively mounted in the interior of said housing,
said preamplifier being further interconnected with said first,
second, and third elements for amplifying said signals, said
amplified signals being delivered to said extending means,
means capable of being mounted on the interior of said housing and
engaging said support mast for rotating said entire housing about
said support mast,
means external of said housing for generating rotate signals in
response to a manual input, and
means for extending said rotate signals from aforesaid generating
means through said housing to said rotate means.
27. The antenna of claim 13 further comprising:
a support mast,
a hollow weatherproof housing having a front, back, top, bottom and
longitudinal sides, said housing having a formed hole in said
bottom and containing said longitudinal support,
a substantially cylindrically shaped gear mast having a bottom end
oriented in the aforesaid hole, said gear mast extending from said
housing bottom to said housing top on the interior of said housing,
said gear mast having a top end engaging the interior of said
housing top, said gear mast being capable of rotating in said
housing, said gear mast being capable of releasably connecting to
one end of said support mast,
a circular gear disposed around and integral with said gear
mast,
a motor with a driveshaft mounted in said housing,
means for operatively interconnecting said driveshaft of said motor
to said gear mast,
means for controlling the position of said housing in relation to
said gear mast, said controlling means being capable of stopping
the direction of said driveshaft when said housing has rotated
substantially 360.degree. about said gear mast, and
means exterior of said housing for generating rotate signals to
said motor in response to a manual input.
28. The antenna of claim 27 wherein said controlling means
comprises a raised notch on the circumference of said gear mast and
a switch mounted to interior of said housing responsive to the
position of said notch.
29. A low and high band VHF antenna comprising:
a longitudinal support,
a first element means mounted on said support,
a second element means mounted on said support, said first and
second element means cooperating to receive low band VHF signals,
said first and second element means each comprising:
(a) opposing element half sections having their inboard ends
mounted to said support, and
(b) A lengthening coil connected to each inboard end and in
substantial alignment with said connected half section, and
a third element means mounted on said support, said second and
third element means cooperating to receive high band VHF signals,
the physical spacings between said first and said second element
and between said second and said third elements on said support
being less than one-tenth the wavelength of the highest frequency
in the high VHF band said half sections of said first element means
being connected to said support and oriented to lay in a plane
substantially perpendicular to the longitudinal axis of said
support, said half sections of said second element means being
connected to said support and oriented to form an open V-shaped
configuration having an apex angle of substantially 135 degrees,
the open end of the aforesaid V-shaped configuration being directed
toward the front of said support, and said half sections of said
third element being connected to said support and oriented to form
an open V-shaped configuration having an apex angle of
substantially 60 degrees, the open end of the aforesaid V-shaped
configuration being directed toward the front of said support.
30. The antenna of claim 29 wherein the physical length of said
first, second, and third elements are the same length.
Description
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to a highly compact all-channel television
antenna. More particularly, it relates to an all-channel television
antenna having the antenna elements the same physical length.
2. Discussion of the Prior Art
Over the past several decades, the art of television antenna design
has become quite sophisticated. Two general consumer categories of
antennas have evolved. The first category contains the
"multi-element" UHF-VHF large antennas which typically comprise
numerous elements in each antenna in order to improve the gain and
directivity of the television signal across the 82 channel VHF-UHF
bands. Examples of such prior art approaches are:
______________________________________ U.S. Pat. No. Inventor Date
______________________________________ 3,531,805 Winegard et al
Sept. 29, 1970 3,475,759 Winegard Oct. 28, 1969 3,329,960 Winegard
July 4, 1967 3,007,167 Winegard Oct. 31, 1961 2,992,430 Winegard
July 11, 1961 3,321,764 Winegard et al May 23, 1967
______________________________________
One such prior art approach is conventionally available from the
WINEGARD COMPANY known as the CHROMSTAR VHF-UHF line of antennas.
The largest of this series is the Model CH-8200 (U.S. Pat. No.
2,992,430) comprising a total of 43 elements (29 UHF elements and
22 VHF elements) having a boom length of 173 inches, a turning
radius of 98 inches, and a maximum width of 108 inches. The
smallest UHF-VHF antenna in the CHROMSTAR series is the model
CH-7074 having a total of seven elements (4 VHF and 3 UHF) with a
boom length of 341/2 inches, a turning radius of 56 inches, and a
maximum width of 108 inches.
In the conventionally available GOLD STAR line from the WINEGARD
COMPANY, the VHF portion of the antennas are substantially "V"
types and the smallest UHF-VHF antenna in this series has a total
of ten elements (3 VHF and 7 UHF) with a boom length of 263/4
inches, a turning radius of 481/2 inches, and a maximum width of 89
inches.
Another series of conventionally available "multi-element" large
antennas available from the WINEGARD COMPANY are called PREMIER "X"
and these antennas intermix both VHF and UHF signals on the same
linear plane. The smallest UHF-VHF antenna in this series has five
elements (Model X-15).
The second general category of consumer VHF-UHF television antennas
may properly be termed "rabbit-ears." The WINEGARD COMPANY also
manufactures a conventional series of VHF-UHF indoor antennas known
as the COLOR CEPTOR line and the POWERBEAM line. All of these prior
art approaches are designed to have a base member which preferably
sets on the top of a television set with at least two upstanding
adjustable antenna elements affixed thereto. In addition, a UHF
upstanding circular element may also be provided. Rabbit ear
antennas, however, are not known for significant response.
A consumer antenna nearing (or approaching) the performance of the
large multi-element antennas, yet combining the size and
lightweight of the small rabbit-ears antennas would form a third
classification of consumer VHF-UHF television antennas. The SENSAR
line conventionally available from WINEGARD COMPANY (Models SR-20A,
SR-30M, and RVH-2K) properly falls in this category.
The Radio Corporation of America (RCA) also manufactures an antenna
in this third consumer category which is identified as Model 5MS550
and termed the AC-DC MINI-STATE ANTENNA SYSTEM. The RCA system
contains a miniaturized uni-directional antenna, a solid state
amplifier and an electrical rotating mechanism all housed inside a
weather-proof housing. The diameter of the housing of the RCA
system is 201/2 inches. The VHF section of the RCA system is a
circular shaped, slot tune, broad band, uni-directional traveling
wave antenna. The UHF section, on the other hand, is a broad band
multi-element array. The VHF signal must be amplified and then is
combined with an unamplified UHF signal by means of an adder
circuit.
The present invention more properly falls in the third category of
consumer antennas. The antenna system of the present invention
performs like a large multi-element antenna twice its size yet
maintains the compactness and lightweightness of the rabbit-ear
consumer category. Like the RCA antenna system, the antenna system
of the present invention utilizes a unique weather-tight housing
and can optionally contain a rotor for rotating the antenna, and a
preamplifier circuit. Unlike the RCA system, the preamplifier is
not necessary for operation of the antenna. The rotor is protected
against dirt and weather for long life and enables the antenna to
rotate substantially 360.degree.. More importantly, and in contrast
to the RCA system, the antenna system of the present invention
utilizes outwardly extending antenna elements for the entire
VHF-UHF band. Unlike the large television antennas of the first
category, the antenna system of the present invention utilizes no
horizontal crossarms or booms, as conventionally termed, and hence
does not require conventional saddle supports of insulating
materials or the like. However, since the antenna of the present
invention does utilize outwardly extending antenna elements, these
elements are positively locked to substantially minimize sagging,
and/or misaligning due to windloading, icing, and the like.
Most fundamentally, the antenna system of the present invention
contains six outwardly extending antenna halves forming three
elements, each having the same physical length. No prior art all
band VHF-UHF television antenna utilizes such an element
configuration. From a manufacturing and cost viewpoint, the antenna
system of the present invention represents a major breakthrough.
Only one size of element need be manufactured and stocked.
The six element halves are combined into three elements wherein the
first and second elements are utilized primarily to receive a VHF
signal in the low band and wherein the second and third elements
are utilized primarily to receive signals in the high VHF band. The
physical spacing between each element is substantially the same and
is substantially less than one-tenth of a wave length of the
shortest VHF wave length.
The VHF frequency range includes a low VHF band of 54 mHz to 88 mHz
(channels 2-6) and a high VHF band of 174 mHz to 216 mHz (channels
7-13). Hence the shortest wavelength in the VHF range occurs at 216
mHz with 54.3"--the one-tenth wavelength being 5.43".
Conventionally the spacings between the VHF antenna elements may be
a quarter wavelength (i.e., 13.6") and the element halves are
interconnected in a crossover fashion (front fed) so that the
combined signals are in phase to be additive. As set forth in U.S.
Pat. No. 3,392,399 (issued to WINEGARD on July 9, 1968) the
spacings between the driven VHF dipoles can be reduced to minimum
spacing of approximately one-tenth of a wavelength with reference
to the high end of the high VHF band. Hence, spacings of 5.75
inches were achieved by using a transmission line having a series
of serpentine or sinusoidal convolutions formed in a plane parallel
to the plane of the dipole elements. The antenna of the present
invention achieves a spacing between the driven elements
substantially less than one-tenth of a wavelength with respect to
the same reference. Again, the high degree of compactness of the
antenna system of the present invention is due in part to the close
physical spacing between the elements as taught in the present
invention. This contributes significantly to the overall
compactness of the antenna and the lightweightness of the antenna.
Significant breakthroughs in manufacturing costs are also
obtained.
As a result, the all band UHF-VHF antenna system of the present
invention, in a preferable embodiment, has a turning radius of just
under 30 inches, a housing longitudinal length of approximately 8
inches, utilization of six identical silver anodized antenna
element halves (three elements), a physical weight in the shipping
carton of less than two pounds, and a weatherproof housing which
may optionally contain a rotor and preamplifier.
SUMMARY OF THE INVENTION
The antenna system of the present invention includes a support
mast, a weatherproof housing, a rotor arrangement, a preamplifier
circuit, and three identically sized silver anodized outwardly
extending elements.
The support mast may include the conventional cylindrically shaped
support mast which can be mounted vertically to the roof or inside
the attic of a building or it may include in another embodiment a
pole similar to the pole supporting pole lamps which can be mounted
on the interior of the building between the floor and ceiling of
the room. The housing can selectively receive different sizes of
diameters of support masts within a preferable range.
The housing of the present invention includes an upper and lower
portion which engage in a weather tight relationship having drain
holes formed in the bottom portion thereof to permit any
condensation from humidity from building up. Furthermore, an
outwardly extending lip is formed around the housing which engages
the circumference of the outwardly extending elements at a
predetermined distance from where the elements are affixed in the
interior of the housing to provide deloading of any moment force
caused by the atmospheric elements on the outwardly extending
antenna elements. The deloading occurs when the lip flexes through
a predetermined apex angle. The engagement of the housing with each
element firmly locks the element in a given configuration.
A rotor mechanism is positioned on the interior of the housing
which includes a motor and a gear mast. The gear mast is capable of
freely rotating on the interior of the housing between the upper
and lower portions and is releasably connected to the support mast.
A rotor motor operatively engages the gear mast to cause the entire
housing to turn about the support mast. A control device senses the
stop position of the gear mast with respect to the housing to
prevent multiple 360.degree. rotation in the same direction.
Disposed on the interior of the housing is a support board to which
the six antenna halves having identical lengths extend therefrom.
The upper and lower portions of the housing provide positive
locking for each half. A first element located at the rear of the
housing forms a dipole in a horizontal plane. A second element is
spaced a predetermined distance from the first element and is
oriented to lay in the same horizontal plane but is further
oriented in a V-type configuration with the apex angle forming
substantially 135.degree. and directed towards the front of the
housing. The third element is also oriented a predetermined
distance from the second element to form an apex angle of
substantially 60.degree. and directed towards the front.
A pair of electrical lengthening coils are connected to the first
element halves and a second pair of electrical lengthening coils
are connected to the second element halves. These two elements in
cooperation with their respective lengthening coils are capable of
receiving composite low band VHF signals. The second element in
cooperation with the second pair of lengthening coils and the third
element are capable of receiving composite high band VHF signals.
The configuration of the third element, by itself, is capable of
receiving UHF signals. The first element also acts as a reflector
for high band VHF signals and the second element acts as a
reflector for signals in the UHF band.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a new and novel
VHF-UHF antenna having a high degree of compactness with good
reception performance.
It is another object of the present invention to provide a new and
novel VHF-UHF antenna wherein all antenna elements are the same
physical length.
It is another object of the present invention to provide a new and
novel deloading device engaging an outwardly extending antenna
element.
It is another object of the present invention to provide a new and
novel waterproof housing for an antenna system.
It is another object of the present invention to provide a new and
novel apparatus for enabling VHF antenna elements to be spaced less
than one-tenth of the wavelength of the highest VHF frequency the
antenna elements are designed to receive.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of the antenna system of the present
invention operatively engaging the ceiling and floor of a room.
FIG. 2 is an illustration of the antenna system of the present
invention being mounted to the roof of a building.
FIG. 3 is an illustration of the antenna system of the present
invention being mounted in an inverted fashion to the inside of an
attic of the building.
FIG. 4 sets forth an exploded perspective view of the various
components of the present invention.
FIG. 5 is a side planar view with partial cut away of the upper
portion of the housing of the present invention.
FIG. 6 is a top planar view of the upper portion of the housing of
the present invention.
FIG. 7 is an end planar view of the upper portion of the housing of
the present invention.
FIG. 8 is a bottom planar view of the upper portion of the housing
of the present invention.
FIG. 9 is a side planar view of the lower portion of the housing of
the present invention.
FIG. 10 is a bottom planar view of the lower portion of the housing
of the present invention.
FIG. 11 is an end planar view of the lower portion of the housing
of the present invention.
FIG. 12 is an upper planar view of the lower portion of the housing
of the present invention.
FIG. 13 is an enlarged prospective view showing the engagement of
an antenna element half with the sides of the upper and lower
housing portions of the present invention.
FIG. 14 is an exploded representation of the view set forth in FIG.
13.
FIG. 15 is an exploded perspective view showing the details of the
interior of the lower housing portion and the rotor motor
mechanisms.
FIG. 16 is a side planar view of the gear mast of the present
invention.
FIG. 17 is a first end view of the gear mast of FIG. 16.
FIG. 18 is the opposing end view of the gear mast of FIG. 16.
FIG. 19 is a bottom planar view of the support circuit for the
antenna element halves of the present invention.
FIG. 20 is a cross sectional view of one antenna element half as it
engages the housing and support board of the present invention
showing the deloading characteristic.
FIG. 21 is an illustration setting forth the orientation of the
antenna elements of the present invention.
FIG. 22 is a graphical response of the antenna of the present
invention in the low VHF band compared to Winegard Model
CH7074.
FIG. 23 is a graphical response of the antenna system of the
present invention in the high VHF band compared to Winegard Model
CH7074.
FIG. 24 is a graphical representation of the response of the
antenna system of the present invention in UHF band compared to
Winegard Model CH7074.
FIG. 25 sets forth the polar diagrams for the antenna system of the
present invention in comparison to Winegard Model CH7074.
FIG. 26 is a schematic diagram of the circuits shown in FIG.
19.
FIG. 27 sets forth the physical size of the antenna of the present
invention in relationship to the Winegard Model CH7074.
FIG. 28 is an illustration setting forth the collapsing of the
antenna elements of the present invention for shipping.
GENERAL DESCRIPTION
The compact antenna system 10 of the present invention is shown in
FIG. 1 installed in a room of a building, such as, for example, an
apartment in an apartment complex. In this environment, the antenna
10 of the present invention is mounted to a support mast 20. The
antenna 10 is cabable of rotation in the directions of arrow 30. In
being rotated in the directions of arrow 30, the antenna will
rotate a full 360.degree. and then stop.
The mast 20 can be of the type conventionally used for pole lamps
and firmly engages the floor and the ceiling of the room although
modified according to the teachings of the present invention.
The compact antenna system 10 of the present invention is capable
of being mounted in a variety of other places such as on the roof
of a building, as shown in FIG. 2, or in the attic or garage of a
building as shown in FIG. 3. In FIGS. 2 and 3, the antenna is
supported by a support mast 40. Mast 40 engages a universal bracket
50 which can be affixed by conventional means to a solid support
such as the main beam of a roof.
As shown in FIG. 1, the compact antenna system 10 of the present
invention has a water proof housing 60 which is mounted to the mast
20 and six silver annodized elements 70 which are of equal
length.
As shown in FIG. 2, the compact antenna 10 of the present invention
is designed to be rotated so that the mid-longitudinal position, as
indicated by arrow 80, for optimum performance of the antenna,
should be directed towards the station to be received.
Hence, it can be observed in FIGS. 1 through 3, that the compact
antenna 10 of the present invention is designed to be utilized
inside the room of a building, the attic of a building, or on the
roof of a building.
FIG. 4 sets forth the various components of the compact antenna
system 10 of the present invention. The housing 60 contains an
upper half 400 and a lower half 402. The two halves are made from
high impact ABS all-weather plastic and are held together to form
housing 60 by means of four screws 404 which engage holes 406 on
the lower half 402 with the holes 408 on the upper half 400. As
previously mentioned, the elements 70 are of equal length and are
made from silver annodized, corrosion protected aluminum material.
These elements are fixedly positioned by the housing 60 by means of
a plurality of slots 410. Hence, when the housing is assembled by
screws 404, the housing fixedly positions the elements at
predetermined angles with each other.
Circuit board 420 contains a grouping of electrical components
which enables the antenna 10 of the present invention to
electrically lengthen the elements 70 and to delay signals
according to the teachings of the present invention.
Positioned above and mounted to this circuit board 420 is a VHF-UHF
solid state signal amplifier 430. This solid state signal amplifier
is optional with the antenna and serves to increase the amount of
signal received by the elements 70 and by the circuit board 420.
One of the features of the present invention relates to the fact
that should this amplifier 430 malfunction, it can selectively be
removed from housing 60 and the antenna 10 of the present invention
will still function to receive signals for the consumer. This
minimizes any inconvenience to the user.
A longer-life optional rotor 440 is also contained within housing
60. The use of the rotor allows the directivity of the antenna to
be utilized and is especially valuable in geographical areas where
the television stations are in different directions. The use of the
rotor 440 also helps to reduce ghosting.
A series of connectors ae provided to the housing 60. Connector 450
is a conventional connector for coaxial cable which interconnects
with the television set. In a preferred embodiment, a predetermined
length of 75-OHM coaxial cable engages connector 450. Connectors
460 are for inter-connecting with the wires which control the rotor
440. These wires are conventional 300-OHM twin lead wire also of
predetermined length. Finally, a stainless steel clamp 470 holds
the antenna housing 60 rigidly to the mast 20.
DETAILED DESCRIPTION
Housing
FIG. 5 sets forth the upper half 400 of housing 60 to include an
upper slanted portion 500 and a lower lip portion 510. Both
portions are integral with each other and are made from high impact
ABS plastic from a single mold.
As shown in FIG. 6, longitudinal sides 600 of the upper slanted
portion correspond to the longitudinal sides 610 of the lower lip
portion 510 in a parallel fashion. The longitudinal edge 600
terminates at one end in a circular edge 620 and terminates at the
opposing end in a flat edge 630.
The edge 610 of the lower lip portion 510 also terminates in a
circular edge 640. The center of the radius of the edge 640,
however, is located at point 642 whereas the center of the circular
edge 620 is located at 622. At the opposing end, longitudinal edge
610 ends in a flat edge 650 which drops to a point substantially
near the longitudinal edge 600. This configuration is specifically
set forth in FIG. 6.
As shown in FIG. 7, the upper slanted portion 500 elevates from the
upper portion 700 of edge 630 and linearly reaches a maximum height
at edge 710. This is clearly shown by reference to FIG. 5 along
line 520. On the contrary, the lower lip portion 510 is flat from
edge 650 to circular edge 640 along line 530 as best shown in FIG.
5. As shown in FIG. 7, the edges 600 of the upper slanted portion
500 tapers slightly inwardly and the engagement with the surface
520 is also rounded.
The lower lip portion 510 includes an outwardly extending lip 540
as best shown in FIG. 5 and a downwardly extending rim 550. As
shown in FIG. 8, the rim 530 is slightly set in from the outer edge
610 of lip 540 as best shown in FIG. 8. The rim 530 extends from
edge 650 along the edges 610 and is concentric to circular edge
640. Formed in the rim 530 at predetermined locations are a
plurality of U-shaped openings designated 700, 710 and 720. These
U-shaped openings are oriented to provide a particular angular
position to the elements 70 as will be more fully described
subsequently.
The interior of the upper housing 400 conforms to the exterior
configuration previously discussed separated by a thin wall
construction. However, centrally disposed on the interior of the
upper slanted portion 500 is a cylindrical protrusion 730 as best
shown in FIGS. 5 and 8. This cylindrical region 730 serves as an
annular receptacle for supporting one end of the mast 20. Disposed
around the cylinder 730 are a series of supports 732, 734 and 736
which provide rigidity to the cylinder 730. In other words, under
severe stress such as in a windstorm, the receptacle 730 will not
dislodge and separate from the upper housing. When the housing is
used in the environment of a room, as shown in FIG. 1, the surface
500 has a hole punched through corresponding in shape to the outer
circumference of the support mast which allows it to pass through.
The rib in the center of receptacle 730 is provided for the top end
of a gear, discussed later, mast to abut. As will be discussed
later the housing is capable of receiving masts having different
diameters.
Finally, a series of holes 740 are formed in a series of upstanding
posts 750.
In FIGS. 9 through 12 are set forth the details of the lower half
402 of the housing 60. The lower half 402, as shown in FIG. 9,
contains a lower plateau region 900, a mid-plateau region 910 and
an upper lip portion 920. Lower plateau portion 900 contains a flat
surface 902 which, as shown in FIG. 10, has a circular hole 1000
formed therethrough and a plurality of holes 1002 disposed around
the hole 1000 and arranged at the corners of a square. These holes
are drain holes and allow any condensation of water which should
form in the interior of the housing to be drained out. Surface 902
is bounded by longitudinal sides 904 which are parallel to each
other and which terminate at one end in a flat edge 906 and in a
circular edge 908 at the opposite end thereof.
The mid-plateau region 910, as shown in FIG. 10, is a substantially
rectangular region bounded on the longitudinal sides by parallel
edges 912 and at opposing ends by parallel edges 914. Disposed on
the mid-plateau surface 910 are two holes 916 through which pass
connectors 460. A raised cylindrical lip 918 is provided centrally
around a hole 919. Through which the coaxial connector 450 is
mounted therethrough. A conventional rubber boot is applied over
the lip when the coaxial cable is affixed to the connector.
A slanted surface 920 is provided between edge 914 of the
mid-plateau surface 910 and edge 906 of the lower plateau region
902. As shown in FIG. 10, tapering occurs along edges 922.
The upper lip 920 is designed to correspond in configuration to the
lower lip portion 510 of FIG. 6. Hence, edge 1020 corresponds to
edge 610, edge 1030 corresponds to edge 640, edge 1040 corresponds
to edge 650 and edge 1050 corresponds to edge 630 in configuration
and dimension.
The lower plateau region 902 tapers from edge 908 into edge 1060
which is circular in shape corresponding substantially to the
radius of curvature of edge 620. Edge 1060 engages parallel
longitudinal sides 1070 which substantially correspond to edges 600
of FIG. 6. A tapered region 1080 exists between edge 1070 and edges
904, 922, and 912. Finally, the rear edge 914 of the mid-plateau
surface 910 tapers upwardly towards edge 1050 which thereupon
engages the vertical end 1090.
It is obvious from inspection of FIG. 9 that should any
condensation occur within the lower housing half 402 that the
condensation will drain downwardly towards the bottom surface 902
and out through the drainage holes 1002.
As shown in FIG. 12, the formed hole 1000 through the lower plateau
902 has a raised lip 1200 on the interior of the lower housing 402.
The raised lip 1200 has outstanding supports 1210 disposed
therearound. On the interior of the housing 402 above the
mid-plateau 910 are two supports 1220 for receiving a sensing
switch, not shown. A formed pillar 1230 engages a hole of the
sensing switch and when melted over the sensing switch firmly holds
it in place against the supports 1220.
The only other times on the interior of the lower housing 402 are a
large number of support posts. Support posts 1240 are designed to
hold the bracket supporting the rotor assembly. Support posts 1250
are designed to hold the circuit board 420. Support post 1260 is
designed to partially support the preamplifier board 430. Formed
holes 406 are designed to aid in engaging the upper housing
400.
Formed on the lip 920 is an upstanding ridge 950, as best shown in
FIGS. 9 and 12. The configuration of ridge 950 is such that it
firmly engages the downwardly extending rim 550 of the upper
housing half 400. Hence, when the upper half engages the lower
half, as will be brought out in greater detail later, a seal is
generated between the two housing halves. A similar ridge or rim
960 is formed on the rear half of the housing 402 and also engages
the corresponding edges 630 and 650 of the upper housing half.
Hence, around the periphery engaging the upper half 400 and the
lower half 402, a water tight seal is formed.
Also formed on the lip 920 are a series of cupped support posts
970, as best shown in FIGS. 9 and 12. Each post 970 has a circular
curved region or cup 972 which receives the bottom circular portion
of an element 70. The longitudinal width of each post 970 is such
that it is slightly less than the width between the U-shaped cavity
710 as shown in FIG. 5. Hence, and as will be subsequently
discussed, the post tightly engages the sidewalls of the U-shaped
cavity 710 to form a circular opening between the upper and lower
housing which engages the antenna element 70. A recessed slot 974
is provided so that all walls are of uniform thickness for molding
purposes.
The details of the interaction between the antenna element 70 and
the upper and lower housing 400 and 402, respectively, are best
shown by reference to FIGS. 13 and 14. When assembled, as shown in
FIG. 13, the downwardly extending rim 550 from the upper housing
400 firmly abuts the upstanding ridge 950 of the lower housing half
402. The area of engagement is designated 1300 in FIG. 13.
Furthermore, the lower surface 1310 of rim 500 firmly abuts and
engages the top surface of lip 920 of the lower housing half. Hence
the area of engagement designated 1330 in cooperation with the area
of engagement designated 1300 provides a water tight seal between
the upper and lower housing halves. This is especially true since
surface 1300 is perpendicular to surface 1330 and this seal will
sustain driven rain in an outside environment.
A water tight seal also exists completely around the circumference
of the antenna element 70 and where it engages the U-shaped slot
710 and the cupped surface 972 of post 970. Since the lower housing
half 402 is firmly affixed to the upper housing half 400, a water
tight seal is maintained around the antenna element circumference
70. However, when water collects on the element and flows along the
element to the housing 60, the water is collected and is disbursed
outwardly of the housing.
As mentioned, a plurality of drain holes 1002 are provided in the
bottom of the housing in order to drain condensation out. Although
the housing 60 is water tight, it is not air tight and air carrying
heavy humidity will normally condense and that condensation will
drain out of the housing. It is to be noted, that due to the
location of the drain holes 1002, it would be virtually impossible
for any water driven in through the drain holes from the ambient
environment outside of the housing 60 to be driven into the
interior above the mid-plateau 910 or above region 1082 of the
lower housing. Even if such moisture were driven that far inwardly,
it would quickly and rapidly drain back out through the drain holes
1002.
In FIG. 15 is shown the rotor assembly 440 of the present invention
to include a rotor motor 1500, a support plate 1510, a gear mast
1520, and a control switch 1530. The combination set forth in FIG.
15 interconnects so that when appropriate control signals are
delivered over terminals 1540, the switch 1530 depending on which
state it is initially in commences to activate the rotor motor 1500
which through drive gear 1550 activates the large gear 1560 on the
gear mast 1520 to rotate the antenna clockwise or counter
clockwise. In order to prevent continuous rotation, a stop 1570 is
provided on the gear mast 1520 to activate the sensor 1580 of
switch 1530 to cause the motor rotor to stop. Rotation, at this
point, is only possible in the opposite direction. The sensor
switch switches 12 volts and is conventionally available from
Guardian Electric or Switchcraft.
The rotor motor is commercially available from ROWE as the 500
series. The mounting plate 1510 is shown substantially configured
so that a formed hole 1512 is slightly larger than the outer
circumference of the upper portion 1522 of the gear mast 1520. In
all other aspects, the mounting plate 1510 has suitable formed
holes so that the motor can be firmly affixed to the mounting plate
and then the mounting plate slidedly engages over the upper
cylindrical portion 1520 of the gear mast and can be affixed by
means of screws or the like to posts 1240.
The gear mast 1520 is of integral construction and is made from
nylon type material. As can be seen by reference to FIG. 15, the
lower portion of 1524 of the gear mast 1520 contains an outstanding
protrusion 1526 to which the mast 20 can be affixed by means of a C
clamp 470 as shown in reference to FIG. 4.
The details of the gear mast 1520 are shown by reference to FIGS.
16 through 18. A series of support bridges 1600 are provided at
90.degree. intervals around the circumference of cylinder 1522 at
predetermined distances above and below the gear 1560. The upper
edge 1610 of these support ridges are designed and located so that
when the assembly shown in FIG. 15 is installed, edge 1610 abuts
support plate 1510 and the lower edge 1620 abuts the rim 1200
surrounding the formed hole 1000 in the bottom of housing 402.
Hence, the gear mast 1520 is held vertically between the upper and
lower housing portions. The upper portion 1522 of the gear is
slightly tapered, about one degree, in decreasing diameter towards
end 1630. When the mast 20 is inserted into the gear mast as shown
in FIG. 4, it will firmly engage along the interior of the gear
mast 1520.
In the preferred embodiment, the gear mast receives masts having
diameters varying from 3/4" to 11/4" although 11/4" is more common.
Longitudinal ribs 1528 are provided at 90.degree. intervals on the
interior of the gear mast to align the mast 20.
The connection portion 1526 is designed to be less than half the
circumference of the gear mast so that the clamp 470 can bias the
mast 20 against the interior of portion 1526. Again, masts of
differing diameters can be utilized since the mast is held against
the protrusion.
The circuit board 420 is shown in FIG. 19 with a number of
components of the present invention mounted thereon. The board
itself corresponds in dimension so that it snugly fits against the
rim 950 of the lower housing, as shown in FIG. 12, and so that the
upper surface 1900 is level with the upper surface of the rim 950.
The board 420 has a large formed hole generally designated 1910
through which the rotor motor 440, the gear mast 1520, and the
balun 2650 pass through as best shown by reference to FIG. 4. The
formed depression 1912 allows for leads to come up into the rotor
motor from the lower housing 402. The protrusions 1914 and 1916
provide added support to the connections width of the board to the
element. The nature and arrangement of the various components shown
on this circuit board will be subsequently discussed.
FIG. 20 sets forth the details of the connection of element 70 and
board 1900 by means of a fastener 2000 engaging a flattened area
2010 of the element 70 and separated from the board 1900 by a lug
spacer 2020. Hence, the element can be pivoted about connector 2000
when the housing is removed. However, the connector 2000 firmly
engages the spacer 2020 so that an electrical connection can be
made. As shown, the element 70 is supported by cup 972 of support
post 970. In this position, the element 70 is slightly spaced above
the upper surface 1900 of board 420. However, the element 70 abuts
the lower surface of lip portion 510.
The interaction of the element 70 with the cup 972 and the lip 510
serves the following functions.
First the interaction provides primary support for the element
thereby minimizing any force for supporting at the terminal or
connector 2000. Sagging and loose electrical connections are
substantially reduced with this approach.
Secondly the antenna elements 70 generate a large degree of force
through a moment arm on the terminal 2000--especially during severe
wind, ice, or the like. To substantially minimize or deload the
effect of this moment arm force at the terminal 2000, the lips 510
and 920 cooperate with each other on the element 70 to provide
relief in the form of a force absorber. As shown by arrow 2030, the
lips 510 and 920 are capable of flexing with the element. Hence,
substantially all of the moment force is dissipated by the lips 510
and 920 before reaching connector 2000. In order to obtain proper
absorption of the force several design factors come into play. One
factor is the width of the lips 510 and 920 designated by arrow
2040. The wider the lips are the greater the absorpotion (and
support). However, a trade-off occurs with cost of materials.
Another factor relates to the material used in making the lips. The
material must be sufficiently flexible so as not to be brittle, yet
not too flexible as to offer no resistance. In the preferred
embodiment, the width of the lip is about one inch although the
width can preferably be in the range of one-half inch to one and
one-half inch. When compared to the length of the element, the
width 2040 is preferably at least 1/54 the length of the element.
The angle of flexing 2030 is preferably in the range of 1.degree.
to 10.degree..
The Antenna Elements
The compact antenna of the present invention has three elements 70.
The first element, as shown in FIG. 21, is made from half sections
E1 and E2. The second element is comprised of half sections E3 and
E4 and are oriented in a V-configuration separated by a preferable
apex angle of 135 degrees. The third element is formed from half
sections E5 and E6, also formed in a V-shaped configuration, and
separated by a preferable apex angle of 60 degrees. As previously
mentioned, all half sections E1 through E6 are of a predetermined
length and, in the preferred embodiment, this length is 27
inches.
The frequency response characteristics for the VHF-UHF bands are
set forth in FIGS. 22 through 24. In generating the test results
for the compact television antenna 10 of the present invention, a
standard of comparison was required. Hence, the same tests were
conducted on the commercially available CHROMSTAR Model CH7074
which is a small VHF-UHF television antenna available from
Winegard.
The response of the antenna 10 of the present invention in the low
VHF band, the high VHF band, and the UHF band will be disussed in
the following. The three elements E1-E2, E3-E4, and E5-E6 respond
differently in each band.
1. Low Band VHF Response
In FIG. 22, the low band VHF response of Model CH7074 is shown in
curve 2200 whereas curve 2210 sets forth the frequency response for
the compact antenna 10 of the present invention. Both antennas were
tested under zero antennuation and the tests were conducted on the
inside test range. The preamplifier in the present invention was
not used in the tests.
The antenna gain comparison between the CH7074 and the antenna of
the present invention is set forth below:
______________________________________ PRESENT CHANNEL REFERENCE
INVENTION ______________________________________ LO-BAND 2 PC 0.0
-7.2 db 4 PC 0.0 -7.0 db 6 PC 0.0 -2.6 db HI-BAND 7 PC 0.0 +1.8 db
10 PC 0.0 -1.4 db 13 PC 0.0 -3.0 db UHF 14 PC 0.0 +0.6 db 41 PC 0.0
+1.5 db 69 SC 0.0 -4.0 db
______________________________________
In operation on the low VHF band, the first element (halves E1 and
E2) is a driven element which resonates in the lower portion of the
low VHF band. Antenna element (halves E3 and E4) resonates
primarily in the upper portion of the low VHF band. Hence, a
composite response curve is shown in FIG. 22, as curve 2210, with a
center substantially around channel 4. In the low band VHF, the
third element (halves E5 and E6) is substantially inactive.
2. High Band VHF Response
FIG. 23 sets forth the high band VHF response for Model CH7074, as
curve 2300, and for the compact antenna 10 of the present
invention, as curve 2310. In this configuration. curve 2310 is also
the composite of two separate resonances. In the high band of VHF,
the second element (halves E3 and E4) resonates in the lower
portion of the high VHF band. The third element comprising (halves
E5 and E6) resonates in the higher portion of the high VHF band
about channel 13. Hence, the composite curve 2310 peaks
substantially around channel 9. The first element (halves E1 and
E2) serves as a reflector in the high VHF band to increase the gain
at the low end of the high VHF band and to give directivity to the
antenna in this band.
3. UHF Band Response
In FIG. 24, the frequency response for the UHF band is set forth.
Curve 2400 respresents the response for Model CH7074 whereas curve
2410 is the response curve for the compact antenna 10 of the
present invention. In this band, only the element, (halves E5 and
E6) is driven. The second element (halves E3 and E4) serves as a
reflector. This reflection from the second element increases the
low end gain of the third element and gives directivity to the
antenna in this band. The first element (halves E1 and E2) is
substantially inactive in the UHF band.
Polar Diagrams
The polar diagrams are set forth in FIG. 25 for the compact antenna
10 of the present invention in comparison to the Model CH7074. The
comparisons of the front-to-back ratios are set forth in the
following table.
______________________________________ Front-To-Back Ratio Channel
Model CH7074 Antenna 10 ______________________________________ 2 6
db 0.4 db 4 6.3 db 0.8 db 6 0.8 db 0.9 db 7 10.5 db 10.2 db 10 20
db 20 db 13 20 db 17.5 db 14 19 db 10.5 db 41 20 db 7.5 db 69 20 db
14 db ______________________________________
The 0.707 beam width comparisons are as follows:
______________________________________ .707 Beam Width Channel
Model CH7074 Antenna 10 ______________________________________ 2
79.degree. 88.degree. 4 68.degree. 90.degree. 6 80.degree.
90.degree. 7 45.degree. 49.degree. 10 56.degree. 52.degree. 13
43.degree. 49.degree. 14 61.degree. 35.degree. 41 68.degree.
28.degree. 69 30.degree. 20.degree.
______________________________________
Circuit Description
FIG. 19 shows the circuit board 420 with the electronic schematic
for this board shown in FIG. 26. This circuit includes a number of
components interconnected as follows. Terminal 2600 is connected to
one end of element half E1 and is further connected to a wire coil
2602 wound on a one-quarter of an inch core comprising 19 turns of
18 gauge wire (approximately 3/4" long). Coil 2602 is oriented as
shown in FIG. 19, for sake of reference, on the board in a vertical
orientation substantially parallel to element half E1.
Correspondingly coupled to terminal 2604 is one end of element half
E2 and a coil 2606 which is also 19 turns of 18 gauge wire wound on
a one-quarter inch core. Coils 2602 and 2606 are substantially
identical in construction and in performance characteristics.
Interconnected between terminals 2600 and 2604 is a capacitor
identified as 2608 which is preferably one pico farad. This
capacitor provides matching on the high VHF band.
Coil 2602 is interconnected diagonally by wire 2610 to coil 2612
which is located in a horizontal plane substantially perpendicular
to coil 2602. Coil 2612 comprises 8 turns of 18 gauge wire wound on
a 3/16 inch diameter (about 1/4" in length). Coil 2612 terminates
at node 2614. Likewise, coil 2606 is delivered diagonally by means
of wire 2616 to coil 2618 which is substantially identical to coil
2612. Coil 2618 is also located in a horizontal plane parallel to
coil 2612 and perpendicular to coil 2606. Coil 2618 terminates in
node 2620.
Element half E3 is connected to terminal 2622 as is one end of coil
2624 which has eleven turns of 18 gauge wire wound on a 3/16 inch
diameter (5/16" long). Coil 2624 is arranged substantially
vertically on the board being substantially aligned with element
half E3 and is interconnected with coil 2618 at node 2620.
Likewise, element half E4 is connected with terminal 2626 which in
turn is connected to coil 2628. Coil 2628 substantially identical
to coil 2624 and is connected at its opposing end to node 2614.
A wire 2630 interconnects node 2620 with coil 2632. The other end
of coil 2632 is directly connected to terminal 2634 which in turn
is connected to element half E6. Likewise, diagonal wire 2636
connects node 2614 to coil 2638. Coil 2638 has its other end
directly connected to terminal 2640. Coils 2632 and 2638 are
substantially identical to each other, each comprising seven turns
of 18 gauge wire wound on a 3/16 inch diameter (1/8" long).
Terminal 2640 is connected over wire 2642 to one input of a balun
generally identified as 2650. The other input of balun 2650 is
connected over wire 2644 to terminal 2634 which is connected to
element half E6. The balun 2650 is a conventional ferrite core 2652
4:1 balun. The 4:1 balun 2650 creates an impedance match from the
300 ohm antenna at terminals 2640 and 2634 to the 75 ohms down lead
at terminals 2656 and 2658. The operation of the circuit as shown
in FIG. 26 in the low VHF band, the high VHF band, and the UHF band
will now be discussed. Before discussing what is believed to be the
operation of the antenna of the present invention, it is to be
noted that antenna theory in general often belies precise
formulation and is rather primarily an art based upon practical
experience and experimentation. This is true for the antenna system
of the present invention.
As pointed out in U.S. Pat. No. 3,392,399, the relative close
spacing presents "a more favorable radiation capture capability for
the antenna . . . while maintaining relatively broad band response
and favorable gain." (Col. 6) In this patent the spacing reached
0.1 wavelength with reference to the high end of the high VHF band
(i.e., 5.43 inches). In the antenna 10 of the present invention the
physical spacing between the VHF elements is about 1.5 inches or
almost 400% shorter than the 399 approach. During experimentation
at these short spacings for the present invention, it was
discovered that if the antenna elements were oriented parallel to
each other very low performance was obtained. However, by
positioning some of the elements in V-configurations a significant
response was obtained. Furthermore, if the elements were spaced
closer than 1.5 inches at the driven end then the response dropped
off. Other acceptance V-configurations are possible on a variety of
shapes, for example, an acceptance combination included: forward V
for element E5-E6, straight for element E3-E4, and reverse V for
element E1-E2. However, the configuration set forth in the drawing
is preferred.
Despite this extreme shortness in spacing, under the teachings of
the present invention relatively broad band response and favorable
gain were achieved similar to that obtained from a conventional
large multi-element antenna such as the Model 7074.
All coils in the circuit discussed above are tightly wound.
1. Low Band UHF Circuit Operation
In the low VHF band, and as previously mentioned, the third element
E5 and E6 is substantially inactive, thus signals in this band are
primarily received from the first and second elements (E1-E2 and
E3-E4, respectively). In the low VHF band, the circuit operates
with the first and second elements as follows.
Coils 2602 and 2606 being tightly wound contain substantial
inductance and electrically lengthens the physical length of halves
E1 and E2 for the first element. In other words, the coils 2602 and
2606 electrically lengthens the 54 inch element E1-E2 so that the
first element substantially half-wave resonates in the lower
portion of the low VHF band.
When a coil having inductance is coupled to a driven element to
lower resonance a certain tradeoff between gain and size occurs
because of capture area loss. Clearly, if no coil were utilized, an
antenna of about 98.4 inches would have to be utilized for 1/2 wave
resonance (at 54 MHZ) in the lower half of the low VHF band. When a
coil is used to lower the resonance of the driven element, the gain
of the element is reduced. Hence, the larger the coil that is added
and the less the physical length of the driven element, the lower
the actual capture area and the lower the gain of the element. This
is the tradeoff occurring in the present invention between element
E1-E2 and coils 2602 and 2606.
It is believed that the coils 2602 and 2606, being oriented
substantially parallel to the E1 and E2 halves, also receives the
low VHF signal.
The same tradeoff in the low VHF band, discussed above, appears for
the relationship between the physical length of the second element
E3-E4 and coils 2624 and 2628. Since one object of the present
invention is to provide a compact antenna wherein the elements are
of the same physical length, by properly designing coils 2624 and
2628, the physical length of the second element halves E3-E4 can be
maintained at 27 inches. Hence, the design of coils 2624 and 2628
in cooperation with the second element is such as to provide
substantially one-half wave resonance in the upper portion of the
low VHF band.
In summary, the design of the first and second elements in
conjunction with the coils 2602-2606 and 2624-2628 are such that a
tradeoff has occurred to optimize the response for the low VHF band
as shown in FIG. 22. The lengthening coils of the present invention
can be adopted for use in antennas designed for frequencies other
than UHF and VHF.
Another consideration in the low VHF band operation of the circuit
is the interaction between the signals received from the first
element E1-E2 and the second element E3-E4. The low band VHF
signals from both elements are combined at nodes 2614 and 2620. The
lower portion low band VHF signals received by the first element
comprising halves E1 and E2 are crossed over via leads 2610 and
2616 to nodes 2614 and 2620 in order to be in proper phase with the
higher portion low band VHF signals appearing from the second
element E3-E4. Hence, in a conventional arrangement, if the
physical distance between the first element E1-E2 were a quarter
wave length spaced apart from the second element E3-E4, the
combined signals would be in perfect phase relationship at nodes
2614 and 2620.
Under the teachings of U.S. Pat. No. 3,392,399 the spacing can
approach 1/10 of the wavelength of the highest VHF frequency or
5.75 inches by using sinuosite feeder lines. However, these feeder
lines are free of any inductance since the curved portions are in
the same plane and any inductance is necessarily cancelled out.
Being formed as a sinuosite, the feeder line is actually a
transmission line of the required quarter-wavelength.
Under the teachings of the present invention, however, a coil
containing inductance is used in place of the sinuosite feeder line
which delays the signal electrically and, hence, operates in
principle differently than the use of sinuosite feeder lines. In
this particular embodiment, the spacing between the first and
second elements is substantially less than the one-tenth wavelength
achieved through use of sinuosite feeder lines.
In the preferred embodiment, the electrical delay is provided by
the inductance of coils 2612 and 2618. Hence, the electrical delay
provided by these coils provides substantially the same phase
matching for the signals from the first and second elements as if
the first and second elements were physically spaced a quarter of a
wavelength apart. This particular approach enables a significant
degree of compactness to occur between the first and second
elements in the VHF band.
While the preferred embodiment uses a cross-over connection for the
delay coils, the principle can be adapted for use in non-crossover,
straight fed situations. Furthermore, the use of the delay coils of
the present invention can be adapted for antenna designs using
frequencies other than UHF and VHF.
It is to be observed, that due to the substantially orthogonal
relationship between the physical positioning of coils 2612 and
2618 and coils 2602-2606 and 2624-2628, the coils 2612 and 2618 do
not add to the capture of the first two elements. At the same time,
the coils 2602-2606 and 2624-2628 do not add to the delay but
electrically lengthens the first two elements. The relationship of
function and performance to the orthogonal oriented coils is of
importance to the operation and contributes to the overall high
degree of compactness enjoyed by the antenna 10 of the present
invention. If coils 2618 and 2612 were removed, the physical
spacing between the first element E1-E2 and the second element
E3-E4 would have to be substantially increased to maintain gain.
Removing coils 2618 and 2612 from the configuration and replacing
it with a solid wire would result in a combined low VHF signal at
nodes 2614 and 2620 of extremely low gain. If coils 2602 and 2606
were removed from the circuit and replaced by straight wire, the
first element E1 would resonate in the FM band and would not
provide an output in the low VHF band of any significance.
By evaluating the overall tradeoffs concerning the capture area and
for coils 2602-2606 and coils 2624-2628 and by providing delay
coils 2612 and 2618 of proper design between the two elements, the
resulting signals from the first two elements (which are
electrically lengthened and are electrically placed in phase by
proper delay inductance) provide an optimum low VHF signal at nodes
2614 and 2620 as shown in FIG. 22.
In the present embodiment, it should also be pointed out that the
response of the antenna 10 could be increased by physically
lengthening the various elements and/or by physically spacing the
elements further apart. However, the tradeoff of response for cost
and installation capabilities must be compared. It is significantly
less costly to produce an antenna wherein all of the elements are
of the same physical length both from a manufacturing and inventory
viewpoint than it is to design an antenna wherein the elements are
of differing lengths and spaced at different distances.
Furthermore, certain asthetic considerations pertaining to consumer
or customer use must be evaluated. It was a goal of the present
embodiment to achieve a highly compact antenna usable, for example,
in the room of a building having a satisfactory response (not
necessarily maximum).
Hence, when manufacturing considerations are evaluated, when cost
considerations are evaluated, when consumer appearance and appeal
are evaluated the antenna 10 of the present invention was arrived
at. Even so, through use of electrical lengthening coils and
through use of electrical delay coils, the antenna 10 of the
present invention has a suitable response characteristic comparable
to a large multi-element antenna such as the Model CH7074.
The combined low VHF band signal appearing at nodes 2614 and 2620
are then delivered through coils 2632 and 2638, in phase, to the
input of the balun 2650.
2. High Band VHF Circuit Operation
In the high VHF band, the circuit shown in FIGS. 19 and 26 operates
as follows. The first element E1-E2 acts as a full wave reflector
for the second and third two elements and is not driven in the high
VHF band. However, the second element E3-E4, as previously
mentioned, substantially full-wave resonates in the lower portion
of the high VHF band. For example, element E3-E4 is electrically
lengthened by coils 2624 and 2628 in the same fashion as priorly
discussed. To the contrary, the third element E5-E6 is not
electrically lengthened but is designed to be driven at full wave
resonance in the higher portion of the high VHF band as is
conventionally done. Hence, the third element exhibits higher gain
due to its natural resonance and the lack of any electrical
lengthening. The higher portion of the high VHF band signals
received by the third element E5-E6 is combined with the lower
portion of the high VHF band signals from the second element E3-E4
on leads 2642 and 2644. Hence, proper phase relationship is
maintained between second and third elements by coils 2638 and 2632
in the same fashion as priorly discussed. The spacing between
terminal 2622 and node 2643 is 13/8".
3. UHF Band Circuit Operation
Finally, the response of the circuit shown in FIGS. 19 and 26 for
the UHF band will be discussed. The coils 2638 and 2632 isolate the
third element E5-E6. Therefore, the third element E5-E6 due to its
significant V-shape resonates (i.e., 2-3 wavelengths) across the
UHF band and with the added gain from the reflector action of the
second element E3-E4, greater gain is delivered on the low end.
Significantly, the physical length of the element and the angular
relationship is such to provide a good response in the UHF band as
shown in FIG. 24.
In FIG. 27, the antenna 10 of the present invention is shown
compared to the Model CH7074 as to physical size. It is to be noted
that Model CH7074 is over twice the size of the antenna of the
present invention and is comprised of seven different sizes in
antenna element lengths. This is compared to the compact antenna 10
of the present invention where one size is used for all
elements.
The distinct advantage of having the smaller physical spacing
between the elements can be appreciated by reference to FIG. 27.
Hence, the overall physical spacing from the first element E1-E2 to
the third element E5-E6 in the antenna 10 of the present invention
is significantly reduced in comparison to the overall length on the
boom of Model CH7074 (i.e., 8" v. 32" a 75% reduction). In Model
CH7074 approximately 420 inches of antenna material is used whereas
in the antenna 10 of the present invention only approximately 162
inches is used. Hence, Model CH7074 has approximately 250% more
material than the antenna of the present invention. Furthermore,
Model CH7074 requires seven different lengths of elements whereas
the antenna of the present invention requires only one length--an
86% reduction. The antenna 10 of the present invention is also
lighter in weight than the Model CH7074. Furthermore, the turning
radius of the antenna of the present invention is approximately 50%
less than the Model CH7074 (i.e., 30" v. 56"). Hence, the antenna
of the present invention can be more easily mounted in attic
environments and can most certainly be mounted in residential
environments such as the living room.
Despite these significant "physical" differences between the
antenna 10 of the present invention and Model CH7074, the
performance characteristics of the two are comparable.
While one basic embodiment of the present invention has been
described in detail herein and was arrived at by weighing all of
the above factors, various changes and modifications can be made
without departing from the scope of the invention. For example, the
delay coils of the present invention, the lengthening coils of the
present invention, or the combination of both delay and lengthening
coils can be adapted for other than UHF and VHF antennas such as FM
antennas. Also, while three elements have been used in the
preferred embodiment, it is to be understood that more than three
elements, such as four elements, could be utilized in conjunction
with the delay and lengthening coils of the present invention. And,
additional reflector elements could be provided to increase
gain.
* * * * *